|MadSci Network: Zoology|
Dear Gerry -
Yes, dogs and cats do have belly buttons. If you can convince a dog or cat to lie on their back for a bit, you'll find it in roughly the same area that humans have a belly button. The belly button, or umbilicus, represents the site where the umbilical cord attaches to the fetus during development. The umbilical cord transports blood between the fetus and the placenta. All eutherian or placental mammals have a placenta, and an umbilical cord. In the placenta the fetal circulation releases wastes in exchange for oxygen and nutrients from the mother. After the baby is born, the umbilical cord is usually tied off and cut. The stump attached to the baby falls off within a few days, leaving the belly button behind as the only reminder of life in utero.
-L. Bry, MadSci Admin
Try the links in the MadSci Library for more information on Zoology.